Thrust grate coolers are used to cool down cement clinker and to recover heat from the heated cooling air. Fine clinker parts which fall through the air supply openings of the grate plates must be caught and carried away.
The cooling air is blown through individual chambers located below the grate and through the air supply openings of the grate plates into the material to be cooled, e.g. cement clinker. It is unavoidable that fine clinker parts also fall through the grate into the individual cooling air chambers. These chambers are under pressure and must be closed, in order that the cooling air does not escape.
In the prior art, funnels closed off with a slide or flap valves were placed under these chambers and the fill state in the funnels was monitored with measuring devices. A partial emptying in a downward direction was performed as needed. The grate screenings were removed by a drag-link conveyor, a drag chain or a conveyor belt which runs under the funnels. Such a customary arrangement is shown in DT-AS No. 19 41 345. The disadvantages of this arrangement reside in the complicated, expensive foundation, the so-called "cellar" which is required to house the funnel apparatus under the cooling air chambers. The cellar sometimes must be blasted into the ground or entails ground water problems.